Travel surveys by telephone: instructions for use
28-06-2010
In “standard Certu” travel surveys, the way of interviewing people - face-to-face or by telephone - is imposed.
In urban environments, why not carry out household travel surveys by telephone? Why not use only the telephone directory to draw out the interview sample? These are two questions often related to costs and convenience. The large amount of information to be collected in household travel surveys makes telephone interviewing difficult. In addition, the fact that not everyone is in the directory introduces a bias in mobility measurement. Those who are not in the directory move around more, but less by car, than the average. Car travel is therefore likely to be overestimated, and walking and public transport underestimated.
The leaflet “Travel surveys by telephone : instructions for use” explains why the “Certu standard” method imposes strict rules and which bias would ensue from not following them.
